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Intraband Dynamics and Terahertz Emission in Biased GaAs/In_(0.53)Ga_(0.47)As Semiconductor Superlattices

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Communications in Theoretical Physics 2009年第12期52卷 1134-1138页

作者： LI Min MI xian-wu College of Physics Science and Information Engineering Jishou University Jishou 416000 China

Using an excitonic basis, we investigate the intraband polarization, optical absorption spectra, and terahertzemission of semiconductor superlattice with the density matrix theory. The excitonic Bloch oscillation is driven by thedc and ac electric fields. The slow variation in the intraband polarization depends on the ac electric field frequency. Theintraband polarization increases when the ac electric field frequency is below the Bloch frequency. When the ac electricfield frequency is above the Bloch frequency, the intraband polarization downwards and its intensity decreases. Thesatellite structures in the optical absorption spectra are presented. Due to excitonic dynamic localization, the emissionlines of terahertz shift in different ac electric field and dc electric field.

关键词： semiconductor superlattices terahertz optical spectra excitons

Design and Implementation of Nonlinear Precoding for MIMO-SDMA Toward 6G Wireless

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China Communications 2024年第1期21卷 69-87页

作者： Chaowu wu Yue Xiao Shu Fang gang wu National Key Laboratory of Wireless Communications University of Electronic Science and Technology of ChinaChengdu 611731China

In this paper,we present a novel and robust nonlinear precoding(NLP)design and detection structure specifically tailored for multiple-input multipleoutput space division multiple access(MIMO-SDMA)systems toward 6G *** approach aims to effectively mitigate the impact of imperfect channel estimation by leveraging the channel fluctuation mean square error(MSE)for reconstructing a highly accurate precoding matrix at the ***,we introduce a simplified receiver structure that eliminates the need for equalization,resulting in reduced interference and notable enhancements in overall system *** conduct both computer simulations and experimental tests to validate the efficacy of our proposed *** results reveals that the proposed NLP scheme offers significant performance improvements,making it particularly well-suited for the forthcoming 6G wireless.

关键词： MIMO-SDMA nonlinear precoding Tomlinson-Harashima precoding(THP) vector perturbation(VP)

Dynamics of Poly(methyl methacrylate)in Ionic Liquids with Different Concentration and Cationic Structures

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Chinese Journal of Polymer Science 2023年第2期41卷 315-324页

作者： Huan Luo Xi He gang Liu Yan-Hua Niu Guang-xian Li College of Polymer Science and Engineering State Key Laboratory of Polymer Materials Engineering of ChinaSichuan UniversityChengdu610065China

The dynamic behavior of entangled poly(methyl methacrylate)(PMMA)chains in both the traditional monocationic ionic liquid(MIL)and synthetic dicationic ionic liquid(DIL)with the same anion bis[(trifluoromethyl)sulfonyl]imide([TFSI]−)has been examined over the wide composition range using differential scanning calorimetry and rheological ***/DIL and PMMA/MIL systems exhibit two glass transitions in the midrange of composition due to self-concentration *** in DIL shows slower relaxation behavior,however,after the iso-free-volume correction,the terminal relaxation timeτ_(0)of PMMA in both the DIL and MIL presents the power law behaviorτ_(0)∼ϕ^(v)with exponent v conforming to experimental results for conventional polymer solutions(v=2.0±0.2).At high ILs concentration(70%),the entanglement molecular weight M_(e)of PMMA/DIL system is lower than that of PMMA/MIL system owing to the formation of additional physical network in DIL,while the difference of M_(e)is reversed at low ILs *** composition dependence might be related to the fact that the probability of formation of physical cross-linking points in linked double imidazolium ring increases with the increase of DIL *** recovered creep strain of PMMA/DIL is almost 18 times of PMMA/MIL,exhibiting significantly better viscoelastic behavior.

关键词： Ionic liquids Terminal relaxation time Entanglement molecular weight Creep-recovery behavior

Necessary Optimality Conditions for a Class of Nonsmooth Vector Optimization

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Acta Mathematicae Applicatae Sinica 2009年第1期25卷 87-94页

作者： Hui-xian wu He-zhi Luo College of Science Hangzhou Dianzi University Hangzhou 310018 China Department of Applied Mathematics Zhejiang University of Technology Hangzhou 310032 China

The Kuhn-Tucker type necessary conditions of weak efficiency are given for the problem of mini- mizing a vector function whose each component is the sum of a differentiable function and a convex function, subjcct to a set of differentiable nonlinear inequalities on a convex subset C of R^n, under the conditions similar to the Abadie constraint qualification, or the Kuhn-Tucker constraint qualification, or the Arrow-Hurwicz-Uzawa constraint qualification.

关键词： Vector optimization problems necessary conditions weak efficiency constraint qualifications

Some Results Associated with the Longest Run in a Strongly Ergodic Markov Chain

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Acta Mathematica Sinica,English Series 2013年第10期29卷 1939-1948页

作者： Ya Zhe ZHANG xian Yuan wu School of Mathematical Sciences Capital Normal University

This paper discusses the asymptotic behaviors of the longest run on a countable state Markov chain. Let {Xa}a∈Z＋ be a stationary strongly ergodic reversible Markov chain on countable- state space S = {1, 2,...}. Let T C S be an arbitrary finite subset of S. Denote by Ln the length of the longest run of consecutive i＇s for i E T, that occurs in the sequence X1,..., Xn. In this paper, we obtain a limit law and a week version of an Erd6s Rdnyi type law for Ln. A large deviation result of Ln is also discussed.

关键词： Longest run Stein-Chen method Poisson approximation

Global Mild Solution of Stochastic Generalized Navier–Stokes Equations with Coriolis Force

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Acta Mathematica Sinica,English Series 2018年第11期34卷 1635-1647页

作者： Wei Hua WANG gang wu School of Mathematical Sciences University of Chinese Academy of Sciences Beijing 100049 P. R. China School of Mathematics and Finance Putian University Putian 351100 P. R. China

In this paper, we apply Littlewood-Paley theory and Ito integral to get the global existence of stochastic Navier-Stokes equations with Coriolis force in Fourier-Besov spaces. As a comparison, we also give correspondi... 详细信息

关键词： Littlewood Paley theory Ito formula stochastic Navier Stokes equations Coriolis force

Sharp upper bounds for the adjacency and the signless Laplacian spectral radius of graphs

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Applied Mathematics(A Journal of Chinese Universities) 2019年第1期34卷 100-112页

作者： wu xian-zhang LIU Jian-ping College of Mathematics and Computer Science Fuzhou University College of Mathematics and Data Science Minjiang University Key Laboratory of Intelligent Metro of Universities in Fujian Province Fuzhou University

Let G be a simple graph with n vertices and m edges. In this paper, we present some new upper bounds for the adjacency and the signless Laplacian spectral radius of graphs in which every pair of adjacent vertices has at least one common adjacent vertex. Our results improve some known upper bounds. The main tool we use here is the Lagrange identity.

关键词： graph spectral radius signless Laplacian spectral radius upper bound

Global Well-posedness of the 3D Generalized Rotating Magnetohydrodynamics Equations

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Acta Mathematica Sinica,English Series 2018年第6期34卷 992-1000页

作者： Wei Hua WANG gang wu School of Mathematical Sciences University of Chinese Academy of Sciences

In this paper, we establish the global well-posedness of the generalized rotating mag- netohydrodynamics equations if the initial data are in χ^1-2α defined by χ^1-2α {u ∈D＇（R^3）：fR^3｜｜^1-2αu^^（ξ）｜d... 详细信息

关键词： Magnetohydrodynamics fractional MHD incompressible rotation framework Coriolis force

Synthesis and Crystal Structure of 3-Benzyl-5-cyclohexylamino-6-phenyl-3,6-dihydro-1,2,3-triazolo[4,5-d]pyrimidin-7-one

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Chinese Journal of Structural Chemistry 2005年第4期24卷 439-443页

作者： ZHAOJun-Feng WANGCheng-gang DINGMing-wu KeyLaboratoryofPesticide＆ChemicalBiology MinistryofEducationCollegeofChemistryCentralChinaNormalUniversityWuhan430079China

The title compound 3-benzyl-5-cyclohexylamino-6-phenyl-3,6-dihydro-1,2,3- triazolo[4,5-d]pyrimidin-7-one (C23H24N6O, Mr = 400.48) has been synthesized by means of tandem aza-Wittig reaction, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to monoclinic, space group P21/n with a = 6.5550(6), b = 10.3711(10), c = 31.265(3) ?, β = 93.827(2)o,V = 2120.8(4) ?3, Z = 4, Dc = 1.254 g/cm3, S = 1.025, μ(MoKa) = 0.081 mm-1, F(000) = 848, R = 0.0576 and wR = 0.1368. X-ray analysis reveals that all ring atoms in the triazolopyrimidinone moiety are almost coplanar and the cyclohexyl ring adopts a chair confor- mation.

关键词： crystal structure 3,6-dihydro-1,2,3-triazolo[4,5-d]pyrimidin-7-one aza-Wittig reaction synthesis